The Canonsburg, Pennsylvania-based company said adjusted earnings were $1.30 a share, down 9% from a year ago. Analysts expected $1.36 a share. Sales dipped 5% to $3.08 billion.

North America segment net sales were down 16% to $1.1 billion, primarily due to lower volumes on existing products, which were largely driven by actions associated with the restructuring and remediation activities at the company's Morgantown plant and the timing of purchases of Mylan products by customers, as well as the impact of the implementation of new accounting standards

Revenue for the year totaled $11.43 billion, down 4% from a year ago. Adjusted earnings came to $4.58 a share, up slightly from a year ago.

For 2019, the EpiPen maker forecast adjusted earnings of $3.80 to $4.80 a share and revenue of $11.5 billion to $12.5 billion. Analysts were looking for earnings of $5.04 a share and sales of $11.9 billion.

During a conference call with analysts, CEO Heather Bresch said that Mylan "made tremendous strides in 2018."

"We've also said many times before that Mylan's business model is built on diversification across our commercial, operational and scientific platforms, making us resilient but not immune to macro industry dynamics and changes within healthcare systems around the globe," Bresch said. "Realizing this, we have focused on our investment and strategic execution, which have yielded a diverse and differentiated business platform. We believe with this diverse platform, we'll be able to continue to deliver superior returns over the long run."

Bresch added that "we remain committed to being a leader for the generics industry and advocate for changes to the current structural issues in the U.S. healthcare system that hinder access to generics."